• Title/Summary/Keyword: Non-contact ultrasonic technique

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Predicting the Firmness of Apples using a Non-contact Ultrasonic Technique

  • Lee, Sangdae;Park, Jeong-Gil;Jeong, Hyun-Mo;Kim, Ki-Bok;Cho, Byoung-Kwan
    • Journal of Biosystems Engineering
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    • v.38 no.3
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    • pp.192-198
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    • 2013
  • Purpose: Methods for non-destructive estimation of product quality have been reported in various industrial fields, but the application of ultrasonic techniques for the agricultural products of potatoes, pears, apples, watermelons, kiwis and tomatoes etc. have been rarely reported since the application of a contact-type ultrasonic transducer in agricultural products is very difficult. Therefore, this study sought to determine the firmness of apples using non-contact ultrasonic techniques. Methods: For this experiment, an ultrasonic experimental tester using a non-contact ultrasonic transducer was created, and a signal processing program was used to analyze the acquired ultrasonic reflected signal. Also, a universal testing machine was used to measure firmness parameters of the apples such as bioyield strength, a firmness factor, after the ultrasonic tests had been performed. Results: Six distance correction factors were calculated to obtain consistent values of ultrasonic properties regardless of the distance between the transducer and the surface of the subject. We developed prediction models of the bioyield strength using the distance correction factors. Conclusions: The optimum prediction model of the bioyield strength of apples using a non-contact ultrasonic technique was a multiple regression model ($R^2=0.9402$).

Guided-Wave Tomographic Imaging of Plate Defects by Laser-Based Ultrasonic Techniques

  • Park, Junpil;Lim, Juyoung;Cho, Younho
    • Journal of the Korean Society for Nondestructive Testing
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    • v.34 no.6
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    • pp.435-440
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    • 2014
  • Contact-guided-wave tests are impractical for investigating specimens with limited accessibility and rough surfaces or complex geometric features. A non-contact setup with a laser-ultrasonic transmitter and receiver is quite attractive for guided-wave inspection. In the present work, we developed a non-contact guided-wave tomography technique using the laser-ultrasonic technique in a plate. A method for Lamb-wave generation and detection in an aluminum plate with a pulsed laser-ultrasonic transmitter and Michelson-interferometer receiver was developed. The defect shape and area in the images obtained using laser scanning, showed good agreement with the actual defect. The proposed approach can be used as a non-contact online inspection and monitoring technique.

Nondestructive Measurement of Cheese Texture using Noncontact Air-instability Compensation Ultrasonic Sensors

  • Baek, In Suck;Lee, Hoonsoo;Kim, Dae-Yong;Lee, Wang-Hee;Cho, Byoung-Kwan
    • Journal of Biosystems Engineering
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    • v.37 no.5
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    • pp.319-326
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    • 2012
  • Purpose: Cheese texture is an important sensory attribute mainly considered for consumers' acceptance. The feasibility of nondestructive measurements of cheese texture was explored using non-contact ultrasonic sensors. Methods: A novel non-contact air instability compensation ultrasonic technique was used for five varieties of hard cheeses to measure ultrasonic parameters, such as velocity and attenuation coefficient. Five texture properties, such as fracturability, hardness, springiness, cohesiveness, and chewiness were assessed by a texture profile analysis (TPA) and correlated with the ultrasonic parameters. Results: Texture properties of five varieties of hard cheese were estimated using ultrasonic parameters with regression analysis models. The most effective model predicted the fracturability, hardness, springiness, and chewiness, with the determination coefficients of 0.946 (RMSE = 21.82 N), 0.944 (RMSE = 63.46 N), 0.797 (RMSE = 0.06 ratio), and 0.833 (RMSE = 17.49 N), respectively. Conclusions: This study demonstrated that the non-contact air instability compensation ultrasonic sensing technique can be an effective tool for rapid and non-destructive determination of cheese texture.

A Structure Non-Contact and Non-destructive Evaluation Using Laser-Ultrasonics Application (구조물의 비접촉 비파괴 검사를 위한 레이저 초음파법 적용)

  • Kim Jae-Yeal;Song Kyung-Seok;Yang Dong-Jo;Kim You-Hong
    • Proceedings of the Korean Society of Machine Tool Engineers Conference
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    • 2005.05a
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    • pp.71-76
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    • 2005
  • The defects evaluation of the interior and the surface would be considered as vital characteristics in predicting the total life span of the steel structure. More importantly, the understandings in the interior composite of welding zone and the notifications in the presence, the formation, and the positioning of the non-metallic inclusion are necessary as well, since there were signs of relatively high defect frequency presented in the welding zone. The ultrasonic testing is a highly recommended technique chosen from among other techniques because of variety of advantages in conducting the non-destructive testing for the welding zone. However, the ultrasonic testing had technical disadvantages referred as followings; the problems due to the couplant between the PZT and the specimen, the formations that were miniature and complex, the moving subject, and the high temperature surrounding the specimen. This research was conducted to resolve the technical disadvantages of the contact ultrasonic testing by studying the non-contact ultrasonic testing where the ultrasonic waves were transferred by the laser, and revealing the specimen defects at its interior part and its surface part. The ultimate goal of this research was to develop a non-destructive evaluation applying the laser manipulated ultrasonic method for the steel structure.

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A Study of Non-contacting Ultrasonic Technique for Evaluation of Fiber Reinforced Composite Materials (섬유강화 복합재료의 비접촉식 초음파 평가 기법 연구)

  • Choi Sang-Woo;Seo Kyeong-Cheol;Lee Joon-Hyun;Byun Joon-Hyun
    • Proceedings of the Korean Society For Composite Materials Conference
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    • 2004.10a
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    • pp.268-271
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    • 2004
  • Non-contact technique should be developed for receiving ultrasonic wave for on-line monitoring of processing defects of fiber reinforced composites, since couplant must be applied on composite materials when conventional ultrasonic testing technique was used. Restriction of conventional ultrasonic testing technique was proven by transmitting and receiving ultrasonic wave on CFRP in various direction of wave propagation with various incident angle of ultrasonic beam. Air-coupled transducer and laser interferometer were applied for non-contacting reception of ultrasonic wave in fiber reinforced composite materials. Air-coupled transducer has optimal sensitivity and frequency band of 300kHz has homogeneous characteristics on direction of wave propagation.

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Internal Defection Evaluation of Spot Weld Part and Carbon Composite using the Non-contact Air-coupled Ultrasonic Transducer Method (비접촉 초음파 탐상기법을 이용한 스폿용접부 및 탄소복합체의 내부 결함평가)

  • Kwak, Nam-Su;Lee, Seung-Chul
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.15 no.11
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    • pp.6432-6439
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    • 2014
  • The NAUT (Non-contact Air coupled Ultrasonic Testing) technique is one of the ultrasonic testing methods that enables non-contact ultrasonic testing by compensating for the energy loss caused by the difference in acoustic impedance of air with an ultrasonic pulser receiver, PRE-AMP and high-sensitivity transducer. As the NAUT is performed in a state of steady ultrasonic transmission and reception, testing can be performed on materials of high or low temperatures or specimens with a rough surface or narrow part, which could not have been tested using the conventional contact-type testing technique. For this study, the internal defects of spot weld, which are often applied to auto parts, and CFRP parts, were tested to determine if it is practical to make the NAUT technique commercial. As the spot welded part had a high ultrasonic transmissivity, the result was shown as red. On the other hand, the part with an internal defect had a layer of air and low transmissivity, which was shown as blue. In addition, depending on the PRF (Pulse Repetition Frequency), an important factor that determines the measurement speed, the color sharpness showed differences. With the images obtained from CFRP specimens or an imaging device, it was possible to identify the shape, size and position of the internal defect within a short period of time. In this paper, it was confirmed in the above-described experiment that both internal defect detection and image processing of the defect could be possible using the NAUT technique. Moreover, it was possible to apply NAUT to the detection of internal defects in the spot welded parts or in CFRP parts, and commercialize its practical application to various fields.

Non-contact damage monitoring technique for FRP laminates using guided waves

  • Garg, Mohit;Sharma, Shruti;Sharma, Sandeep;Mehta, Rajeev
    • Smart Structures and Systems
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    • v.17 no.5
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    • pp.795-817
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    • 2016
  • A non-contact, in-situ and non-invasive technique for health monitoring of submerged fiber reinforced polymers (FRP) laminates has been developed using ultrasonic guided waves. A pair of mobile transducers at specific angles of incidence to the submerged FRP specimen was used to excite Lamb wave modes. Lamb wave modes were used for comprehensive inspection of various types of manufacturing defects like air gaps and missing epoxy, introduced during manufacturing of FRP using Vacuum Assisted Resin Infusion Molding (VARIM). Further service induced damages like notches and surface defects were also studied and evaluated using guided waves. Quantitative evaluation of transmitted ultrasonic signal in defect ridden FRPs $vis-{\grave{a}}-vis$ healthy signal has been used to relate the extent of damage in FRPs. The developed technique has the potential to develop into a quick, real time health monitoring tool for judging the service worthiness of FRPs.

Non-contact Ultrasonic Inspection Technology of Fillet Weldments (필렛 용접부의 비접촉 초음파 검사 기법)

  • Park, Ik-Keun;Lee, Chul-Ku;Kim, Hyun-Mook;Park, Tae-Sung;Kim, Yong-Kwon;Cho, Yong-Sang;Song, Won-Joon;Ahn, Houng-Kun
    • Journal of Welding and Joining
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    • v.23 no.5
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    • pp.37-42
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    • 2005
  • The non-destructive Inspection of the fillet weldment has difficulties due to its geometrical complexity and uneasy access. The surface shear horizontal wave (SH-wave), however, has been successfully applied to the detection of cracks on the surface and sub-surface of the filet weldment heel part. The conventional ultrasonic inspection using the surface SH-wave is usually a contact method using piezoelectric transducer. Thus, it is not suitable for a field application because the reliability and repeatability of inspection are significantly affected by test conditions such as couplant, contact pressure and pre-process. In order to overcome this problem, a non-contact SH-wave inspection method using EMAT is propose. The experimental results with this non-contact method are compared with those with a conventional ultrasonic method in fillet weldment with slit type defects. It is shown that the non-contact inspection technique requires simple procedure and less time in the fillet weldment inspection.

Evaluation of Laser-based Ultrasonic Signals due to Fiber Orientation of CFRP (CFRP의 섬유강화재 배향성에 따른 레이저유도초음파 신호특성 평가)

  • Choi Sang-Woo;Lee Joon-Hyun;Byun Joon-Hyung;Seo Kyeong-Cheol
    • Proceedings of the Korean Society For Composite Materials Conference
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    • 2004.04a
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    • pp.143-146
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    • 2004
  • Fiber reinforced plastic material should be inspected in fabrication process in order to enhance quality by prevent defects such as delamination and void. Generally, ultrasonic technique is widely used to evaluate FRP. In conventional ultrasonic techniques, transducer should be contacted on FRP. However, conventional contacting method could not be applied in fabrication process and novel non-contact evaluating technique was required. Laser-based ultrasonic technique was tried to evaluate FRP plate. Laser-based ultrasonic waves propagated on CFRP were received with various transducers such as accelerometer and AE sensor in order to evaluated the properties of waves due to the variation of frequency. Velocities of laser-based ultrasonic waves were evaluated for various fiber orientation.

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Non-contact sensor to detect movement of dementia patient

  • Rei Satoh;Seigo Ariki;Takakazu Ishimatsu;Nobuoh Matsuzaka;Ung, Kang-Chul
    • 제어로봇시스템학회:학술대회논문집
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    • 2001.10a
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    • pp.89.5-89
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    • 2001
  • In this paper we explain about systems developed to forecast the standing up of the dementia patients. Basic idea of our approach is to measure the respiration and body movements in the bed. Based on the data measured, forecasting of standing up action from the bed is possible to some extent. First system proposed uses an image processing technique. Data obtained about the respiration and movements are used to forecast the standing up of the patients. The second system uses ultrasonic sensors, which emits and receives ultrasonic signals. Two techniques f the ultrasonic sensors are considered. One technique is to emit ultrasonic burst signals and to detect the instance when ...

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